Those of us interested in past beliefs about magic do a lot of hoping and wishing. Like, it's true this text was written two centuries after the events it describes, but maybe it is based on earlier sources or a strong oral tradition. Or, yes, there are other possibilities, but isn't the most likely explanation that this body was a victim of human sacrifice?
But sometimes the evidence is pretty much irrefutable, and can say with very little doubt that we are reading about or looking at an actual witch or wizard, someone who was deeply learned in an ancient, arcane tradition. One of those cases is the woman I will call the Sorceress of Fyrkat, although technically she is the occupant of Fyrkat Grave 4.
Danish National Museum interprets it as you see here, as a shawl so thin as to be nearly transparent. This would have been a highly stylist get-up at the time, just like those worn by noble women in the German empire. Rich Norse women usually held their attire together with a lot of fancy pins and brooches, but this tailored dress needed no such fasteners. She was laid in the bed of a wagon. Wagons like this were standard coffins for high status women in this age, showing that while alive they did not have to walk but were driven everywhere.
You may be wondering why I haven't called Fyrkat 4 a völva, since that is how modern writers usually refer to Norse magical women or prophetesses. But the Old Norse terminology of magic and magical practitioners is one of those topics that, once you dive into it deeply, you wish you hadn't. There are several terms that all shifted meaning over the centuries. It is quite possible that this woman considered völva such an unbearable insult that she would have had her men cut your tongue out for calling her one, before prophesying ruin for your whole family. (Like "witch.") So it is safer to avoid Norse terms altogether and use something generic and English. Incidentally you may think you know why a Norse wise woman was called a völva, which looks like an evocation of feminine mystery. Really it means "staff bearer". Which brings me to the other incontrovertibly magical item from Fyrkat 4, a badly corroded iron staff or wand with bronze fittings.
The chest at the feet of Fyrkat 4 was old and had been repaired multiple times with different sorts of wood, which is an odd detail. It contained mostly clothing, of which all that survived was a quantity of gold and silver thread. So very fancy clothes. There also a set of the standard objects buried with Viking women: shears, a spindle whorl, another whetstone.
The Fyrkat sorceress must have been a formidable woman. Rich, she spent much of her money on exotic goods from far away, favoring in particular fashions that had not been adopted by her peers. And she was, in an allegedly Christian kingdom, a devotee of an ancient magical tradition.
That tradition had many elements. The best known and probably central was prophesying. The sagas tell us that seers regularly traveled through the Norse lands, calling at each prominent farm. There they were lavishly welcomed and they and their followers provided with a feast. They presided over a ritual that involved chanting and, in pre-Christian times, animal sacrifice. They then dressed up in an elaborate costume –was this when the Fyrkat sorceress painted her face white? – took their place on a chair atop a platform and prophesied what the year would bring for the household. According to our sources, they usually provided good news. Again according to our sources, they could be bribed, and would issue better prophecies for those who fed them better. This same accusation was of course made about oracles in the ancient world and is still made about modern shamans, often by other shamans, so this debate seems to be part and parcel of the whole business of prophesying.
Notice that the saga sources say little about the seeress going into trance or ecstasy. But henbane is no trivial drug, and anyone who took enough might go very far indeed past the rational state. Plus ecstasy of one kind or another is almost universally part of the prophetic tradition. So I think we should imagine that Norse seeresses at least sometimes drugged themselves into a trance state to seek answers to pressing questions. One thing we have learned from modern shamans is that they are capable of working in multiple modes, giving pat answers to standard questions – yeah, sure, you'll have a great harvest, what are we eating? – while also drugging or otherwise driving themselves into very dangerous trance states when confronted with a real crisis.
I have also refrained from calling Fyrkat 4 a seeress, which is how the Danish National Museum titles her. I did this because the Norse magical tradition also included other elements besides prophecy, among them the standard repertoire of cunning folk: healing, finding lost objects, making protective amulets, and so on. They were also said to summon storms and curse their enemies to death. I assume that the Fyrkat sorceress engaged at least in healing, and it is fun to imagine that sometimes King Harald sent his bishop away and asked his sorceress to curse his enemies or seek a vision of how his upcoming wars might go.
Much of this material comes from Neil Price, The Viking Way: Magic and Mind in Late Iron Age Scandinavia.